Abstract:
An electrical interconnect includes a woven mesh in which an array of parallel wires is retained in spaced relation by a transverse array of nonconducting strands, the mesh being enclosed or encased within a resilient matrix. The conductive wires are on a close pitch to yield greater current carrying capacity and achieve a lower more stable resistance. With this construction a great number of wires are in contact with each contact pad to yield greater current carrying capacity and corresponding lower resistance. The closer pitch wires also provide greater redundancy of contact points. This structure can be custom configured in as many layers or in a variety of shapes as is desirable to achieve a given electrical performance. The woven mesh can be wrapped around a shaped substrate to provide electrical connections in a desired shape. The woven mesh interconnect can be integrated as part of a boot, wherein the boot receives an electrical device therein and the woven mesh interconnect provides electrical connection from the device within the boot to outside the boot. The woven mesh interconnect can be layered and shaped to form an interconnect which not only provides electrical interconnection but also provides a biasing force due to the shape of the device.
Abstract:
A simple, inexpensive, drillable, reduced CTE laminate and circuitized structures comprising the reduced CTE laminate, is provided. The reduced CTE laminate comprises: from about 40% to 75%, preferably from about 55% to 65%, by weight resin; from about 0.05% to 0.3%, preferably from about 0.08% to 0.10%, by weight curing agent; from about 25% to 60%, preferably from about 30% to 40%, by weight, woven cloth; from about 1% to 15%, preferably from about 5% to 10%, by volume, non-woven quartz mat. The present invention also generally relates to a method for reducing the CTE of circuitized structures, and to methods for making reduced CTE laminate and circuitized structures comprising reduced CTE laminate. The method for making reduced CTE laminate and laminate structures comprises the following steps: providing non-woven quartz mat; providing a prepreg, preferably B-stage cured to not more than about 40%, preferably not more than 30% of full cure; sandwiching the non-woven quartz mat between two layers of prepreg, and reflowing the resin of the prepreg into the quartz mat. Optionally, the reduced CTE laminate is sandwiched between two layers of metal, preferably copper.
Abstract:
A method for coating cloth especially fiberglass sheets with a resin and resulting structure is provided. The coating is performed in two steps. In the first step, essentially all of the strands of the fiberglass are coated with the resin solvent mixture as well as most of the interstices or openings, although some of the interstices or openings have holes where the coating does not completely fill in. This first coating is then partially cured to the extent that it will not redissolve in a second coating of the same resin solution. The coated fiberglass with partially cured resin thereon is then given a second coating of the same resin mixture which coats the first coating and fills in any holes in the first coating. This second coating is then partially cured, which advances the cure of the first coating and results in an impregnated fiberglass cloth structure for use as sticker sheets. This substantially reduces pinholing.
Abstract:
A method for coating cloth especially fiberglass sheets with a resin and resulting structure is provided. The coating is performed in two steps. In the first step, essentially all of the strands of the fiberglass are coated with the resin solvent mixture while maintaining the interstices or openings essentially free of the solvent mixture. This first coating is then partially cured to the extent that it will not redissolve in a second coating of the same resin solution. The coated fiberglass with partially cured resin thereon is then given a second coating of the same resin mixture which coats the first coating and fills in the interstices between the fibers. This second coating is then partially cured, which advances the cure of the first coating and results in an impregnated fiberglass cloth structure for use as sticker sheets. During lamination, the first coating acts like an impenetrable insulating sheet, preventing resin displacement and, therefore, preventing glass fiber contact with the conductive planes. The second coating is fluid enough to fill in spaces in the planes and to form the adhesive bond to cores and conductive layers.
Abstract:
The present invention relates to a glass fabric produced with zero-wist yarn, its use an the manufacture of printed circuits and in numerous other industrial applications, as well as to a process for the manufacture thereof.
Abstract:
Improved thermal characteristics are obtained in a multi-layer substrate for mounting a semiconductor device. A prepeg layer disposed in close proximity to or immediately adjacent to a semiconductor device is formed incorporating an integral, thermally-conductive mesh or screen. The prepeg layer is preferably a sandwich structure of two BT-resin layers (films), between which is disposed a copper screen. In this manner, heat is conducted away from an operating device by an integral part of the substrate, without the need for additional slugs or heat sink structures. Utility for multichip modules is also disclosed.
Abstract:
Dimensionally stable laminates of epoxy resin reinforced with glass fibers have a coefficient of thermal expansion which matches that of copper, making possible copper foil covered laminates which provide improved registration in multilayer printed circuit boards. New glass fabric styles provide balanced thermal expansion in both the warp and fill directions.
Abstract:
A process for the production of a copper-clad laminate which is improved in dimensional accuracy and freedom from bow and twist and shows nearly the same values of dimensional accuracy, thermal expansion coefficient and elastic modulus in the length and width directions, the process using:a prepreg (I) comprising a glass cloth (I-1) having a thickness of 190.+-.20 .mu.m, a weight of 210.+-.20 g/m.sup.2, warp and weft counts of 35 to 38 yarns/25 mm and a warp and weft difference of 2 yarns or less in count, anda copper foil (II) having a ductility, measured in atmosphere at 180.degree. C. in length and width directions, of at least 10% when it is a 1/2 oz/Ft.sup.2 foil, at least 15% when it is a 1 oz/Ft.sup.2 foil and at least 20% when it is a 2 oz/Ft.sup.2 foil, andthe set of the prepreg or prepregs and copper foil or copper foils is laminate-molded by curing it under predetermined heat in a laminate-molding step using a press machine, removing the application of pressure and then cooling the resultant laminate in the press machine.
Abstract:
A fabric for a printed circuit-board characterized by that it is composed of one or more fiber(s) selected from the group consisting of polyether ether ketone fiber, polyetherimide fiber and polysulphone fiber, and glass fiber, and a printed circuit-board employing the fabric as its base material.
Abstract:
A circuit board having multiple layers of a dielectric material, multiple layers of a conductive metal and multiple layers of graphite bonded together to form a composite multilayer printed circuit board having a desired coefficient of expansion and having strip and microstrip transmission lines for electrically connecting very high frequency electronic components mounted on the circuit board. The multiple layers of graphite are positioned in a symmetrical manner with respect to the thickness of the circuit board and selected in number to provide the circuit board with a desired coefficient of expansion. In addition, at least some of the layers of graphite are positioned in close proximity to some of the layers of conductive metal to provide enhanced thermal conduction from the mounted components.